Rotary engine



United States Patent 1,093,278 4/1914 Loftus 123/12(A) 1,386,394 8/1921 Cage ..l.23/65(Bl)(UX) Primary ExaminerAlan D. Herrmann Attamey-Maybee & Legris ABSTRACT: A rotary internal combustion engine comprises a precompressor and a combustion chamber, each comprising a ring gear, a pinion gear meshing with the ring gear, and a member of cresecnt-shape cross section cooperating with the teeth of the gears. The pinion gear teeth cooperate with the ring gear teeth and the crescent-shaped members to define first and second series of successively contracting and expanding closed pockets. Fuel mixture is precompressed in the first series of pockets and admitted through ports into the combustion chamber, the cooperating gear teeth of which constitute piston and cylinder-like devices wherein the precompressed mixture undergoes a combustion cycle to drive the engine. The cooperating gear teeth are of involute form, and the teeth of the pinion gear are preferably hollow, resilient, open ended members.

PATENTED M822 1970 SHEET 1 OF 5 mm 57 NOW 3w ATTORNEYS PATENIED 050221970 3548389 SHEET 2 [IF 5 v I iNTOR. JOHN O. EEK

ATTORNEYS PATENTEDBEEZZIQYB 3,548,789

SHEET u 0F 5 INVENTOR.

JOHN O. CREEK ATTORN EYS I PATENTED m 1976 48789 SHEEISOFS INVENIOR.

JOH N O. CREE K BY%7 f aaly ATTORNEYS ROTARY ENGINE BACKGROUND OF THE INVENTION This invention relates to rotary combustion engines.

Conventional internal combustion engines of the reciprocating piston-type are liable to be noisy and the relatively sliding surfaces thereof are subjected to heavy wear under load. In order to overcome these disadvantages numerous proposals have been put forward to arrange a number of pistonlike members radially with respect to one another in the form of a rotor which cooperates with an annular member providing a series of radially disposed cylinders with which the pistonlike members engage during rotation of the rotor. The rotor cooperates with the annular member in the manner of a pinion with a ring gear in an epicyclic gear train. The pistonlike members define with the cylinders a series of contracting and expanding pockets, to each successive one of which a mixture of air and fuel is admitted prior to contraction of the pocket, the compressed mixture being ignited and the combustion products being subsequently expanded, and exhausted through a port or valve when the available work has been extracted.

The prior proposals do not fully overcome the problem of noise and wear, and the proposed designs do not in general readily admit of adequate cooling and lubricating facilities in larger, more powerful engines. The problems of noise and vibration are closely associated with engine design and can only be overcome by providing an engine which is completely dynamically balanced. Another serious problem is the problem of providing adequate and reliable sealing means between the surfaces of the pistonlike members and the cylinder walls. I

It is an object of the present invention to provide an engine construction which is completely dynamically balanced.

Another object of the invention is to provide a rotary engine construction which is quieter and smoother in operation than known engine engine constructions.

Another object of the invention is to providea rotary engine construction in which the problem of excessive wear is substantially overcome.

Yet another object of the invention is to provide a rotary engine of the type referred to in which the pistonlike members are constructed so as to minimize leakage past their surfaces.

SUMMARY OF THE INVENTION A rotary internal combustion engine according to the present invention essentially includes a rotary cylindrical chamber providing an internally toothed ring gear, a pinion gear offset from the axis of rotation of the chamber and meshing with the teeth of the ring gear to define a series of contracting and expending closed pockets, and a stationary member of crescent-shaped cross section located within the chamber, the member having a convex cylindrical surface disposed in sliding contact with the teeth of the ring gear and a concave cylindrical surface disposed in sliding contact with the teeth of the pinion gear. The engine includes fuel intake means for delivering fuel mixture to each of the series of pockets in turn, the fuel mixture being successively com pressed, ignited and discharged from the pocket as the chamber rotates and finally exhausted from the chamber. In a preferred embodiment of the invention the engine includes two rotary cylindrical chambers, constituting a precompression chamber and a combustion chamber, each chamber providing an internally toothed ring gear meshing with a pinion gear and cooperating with a stationary crescent-shaped member as described above to provide a first series of contracting and expanding pockets in which the fuel mixture is compressed and a second series of contracting and expanding pockets in which the fuel mixture is further compressed, ignited, and expanded, the combustion products being exhausted through a port or valve.

The pinion gear and ring gear are preferably of involute form. It is desirable that the pinion gear teeth should make good-sealing contact with the ring gear teeth, and according to the invention this may be achieved by constructing the pinion gear teeth as resilient, hollow, open ended members, the ends of the teeth sealingly engaging the end walls of the cylinder. Any fuel mixture which leaks into the gear teeth cavities through their open ends is withdrawn through ports in the pinion gear into a chamber, whence it is recirculated.

BRIEF DESCRIPTION OF THE DRAWINGS One rotary internal combustion engine according to the invention will now be described by way of example with reference to the accompanying drawings, in which:

FIG. 1 is a central longitudinal section through the engine;

FIG. 2 is a rear end elevational view of the engine on line 2-2 in FIG. 1; I

FIG. 3 is a front end elevational view of the engine on line 3-3 in FIG. 1;

FIG. 4 is a section on line 4-4 in FIG. 1;

FIG. 5 is a section on line 5-5 in FIG. 1;

FIG. 6 is a fragmentary view of a used scrubber used in association with the external cooling system of the engine;

FIG. 7 is a section on line 77 of FIG. 1;

FIG. 8 is a section on line 8-8 in FIG. 1;

FIG. 9 is an end view of a detail of a modification of FIG. 8; and

FIGS. 10 and 11 are fragmentary perspective views of a detail of the structure shown in FIG. 8.

DESCRIPTION OF THE PREFERRED EMBODIMENTS teeth 11 of involute form, and a second internally toothed ring gear 12 having teeth 13 which are also of involute form. The two ring gears 10 and 12 are coaxially arranged, and it will be noted from FIGS. 7 and 8 that they have the same number of teeth, in the present example six teeth. Connected to the ring gears 10, 12 by long bolts 15, 16 respectively, are three rigid casing members, namely a flanged casing member 17 having an annular flange l8 and a tubular shaft portion 19, a double flanged member 20 having annular flanges 21 and 22 interconnected by a cylindrical portion 23,.and a flanged member 24 having an annular flange 25 and a tubular shaft portion 26; the three casing members, 17, 20 and 24 form a rigid rotary casing which defines with the ring gears 10 and 12 a cylindrical precompression chamber 27 and a cylindrical combustion chamber 28. The ring gears 10 and 12 are formed with integral external cooling fins 29 which are shrouded by casings 30 and 31 (see FIGS. 2 and 3); only one casing 31 is shown in section in FIG. I.

The stator assembly comprises a support structure consisting of front and rear cross members 32 and 33, which are interconnected by tubular frame members 34, and pedestals 35 and 36 bolted to the cross members. The pedestals are formed with coaxial circular openings. The pedestal 36 provides an axially extending annular shaft portion 37 having a flange 38 to which an annular oil reservoir 14 is bolted. Keyed to the shaft portion 37 by a key 39 is a further stationary shaft 40 having an end flange 41, to which are secured a cylindrical shaft 32 extending across the chamber 28 and a member 43 of crescent-shaped cross section, as best seen in FIG. 8. The shaft 42 is secured to the flange 41 by a bolt 44 and the member 43 is secured to the flange by bolts 44 and dowel 45. The shaft 42 is connected by bolts 46 to a further element of the stator assembly, the further element comprising ahollow shaft 47 extending across the precompression chamber 27 and a member 48 of crescent-shaped cross section, which is best seen in FIG. 7. The member 48 extends across the chamber 27. A stub shaft 49 having an annular flange 50 is secured to the shaft 47 and member 48 by bolts 51 and dowel 52. It will be noted that the stub shaft 49, shafts 47 and 42, members 48 and 43, flange portion 41, shaft 40 and shaft portion 37 are rigidly interconnected and constrained not to rotate.

A pinion gear 53 is rotatably supported on the hollow shaft 47, the shaft providing an axis of rotation which is parallel to the main axis of the rotor assembly and radially spaced therefrom. The pinion gear 53 is formed with three radial teeth 54 of involute form, form, which mesh with the teeth 11 of ring gear to provide a series of pockets which contract and expand as the ring gear rotates, the pinion gear teeth closing the pockets sequentially. The pinion gear teeth are resilient, hollow, open ended members which are capable of some elastic deformation under load so as to provide sealing engagement with the ring gear teeth. The flanges 18 and 21, whose inner surfaces provide end walls to the cylindrical precompression chamber 27, sealingly engage the ends of the ring gear teeth 11 and the pinion gear teeth 54. The member 48 of crescent-shaped cross section provides a convex cylindrical surface 48a which is coaxial with the ring gear 10 and adapted to make sliding contact with the tips of the ring gear teeth 11 during their movement, and a concave cylindrical surface 48b which is coaxial with the pinion gear 53 and adapted to make sliding contact with the tips of the teeth 54. As shown in FIG. 7, the ring gear teeth 11 provide six pockets a, b, c, d, e and f which correspond to cylinders in a reciprocating piston-type engine, the pinion gear teeth 54 corresponding to the pistons. FIG. 7 shows the assembly at a particular instant during rotation, pocket a of the line being closed by the member 48, pocket b being in a state of contraction, and pocket c being in a state of expansion.

Rotatably supported on the shaft 42 is a second pinion gear 55 having involute gear teeth 56 which mesh with the teeth 13 of ring gear 12 to provide a second series of successively contracting and expanding closed pockets g, h, i, j, k and l. The gear teeth 56 are formed with part-cylindrical recesses 57 at their outer surfaces or tips so as to provide a residual space even'when a pocket is contracted to the fullest extent. The gear teeth 56 are resilient, hollow, open ended members capable of elastic deformation under load to ensure sealing contact with the teeth 13.

The member 43 of crescent-shaped cross section has a convex cylindrical surface 43a which is coaxial with the ring gear 12 and adapted to make sliding contact with the tips of the gear teeth 13, and a concave cylindrical surface 43b which is coaxial with the pinion gear 55 and adapted to make sliding contact with the outer surfaces or tips of the pinion gear teeth The tubular shaft portion 19 of member 17 is joumaled for rotation in a bearing 58 carried by the pedestal 35. Annular grooves 59 connected by ducts 60 to an oil reservoir 61 provide lubrication to the bearing surfaces. An output shaft 62 is constituted by an axial extension of shaft portion 19.

Mounted on pedestal 35 is a flanged throat member 63, to the upper flange of which a carburetor is connected for supplying fuel mixture to the engine. The tapering throat of the member 63 terminates at an opening 64 in the bearing 58 which registers with a ring of ports 65. The tubular shaft portion 19 provides an internal passageway terminating in an end opening 66, which registers with a passageway 67 in the stub shaft 49, the latter communicating with the chamber 27 by way of an end opening 68.

In operation of the engine, fuel mixture and lubricant in atomized form are admitted through the ports 65 to the interior of the rotary shaft portion 19, and supplied by way of opening 66, passageway 67 and opening 68 to the interior of chamber 27. Lubricant from the mixture is also conveyed to the surfaces of a bearing sleeve 69 interposed between the stationary stub shaft 49 and the rotary casing member 17, by way of a ring of ports 70. Fuel mixture admitted to the space 71 of the precompression chamber (see FIG. 7) becomes trapped in each pocket in turn on reaching the position of pocket a and is compressed by the action of the pinion gear teeth. In pocket b the fuel mixture is being compressed and is being forced down a radial passageway 72, the mixture passing into a space 73 within the shaft 47 by way of a port 74. The compressed mixture passes through further passages and 81 into the combustion chamber 28, the mixture being first admitted into a cavity 82 within the member 43. The cavity 82 communicates with a port 83 through which the mixture is admitted to the pockets gl in turn. In the position shown in FIG. 8, the port 83 is closed by a gear tooth 13, but on further rotation of the gear, fuel mixture will be admitted to the pocket g. In pocket h the mixture is being further compressed. Pocket i is in a firing position, the mixture therein being fully compressed ready for ignition. After ignition the combustion products expand as in pocket j and are finally discharged.

It will be noted that the member 43 is formed with a bypass passage 84 to provide for a further expansion of the combustion pocket for the combustion products up to the point of exhaust.

For ignition of the mixture in the combustion chamber, a number of spark plugs 85, one for each pocket, are set in the annular flange 25. Each spark plug 85 provides a spark gap 86 between a pair of electrodes, one of which is connected to the metal casing, the other electrode being insulated from the casing and connected to an external electrode 87. The spark plugs 85 are positioned on a circle such that the external electrodes cooperate in cyclic succession with a high tension electrode 88 mounted on a support member 89 supported by the stator assembly. The electrode 88 is electrically connected to a high tension supply means, (not shown) the high tension supply means includes a cam-operated breaker switch (not shown) driven by a gear 90 mounted on the rotary shaft 19.

The tubular portion 26 of the casing member 24 is joumaled on the stationary shaft 40, a bearing sleeve 91 being interposed between the relatively sliding surfaces of the shafts. Oil

from the oil reservoir 14 is delivered to the bearing surfaces by means of an annular, dish-shaped oil slinger 92 which is secured to the sleeve 91 and rotatable therewith.

An induction fan 93 is mounted at front end of the engine and arranged coaxially with it. The fan comprises a hub structure 94 on which an impeller 95 is mounted by bearings 96, the hub structure being connected to the pedestal 36 of the engine support structure. The fan has a housing 97 providing a circular opening 98 on the axis of the engine, and an exhaust passage 99 terminating in an exhaust opening 100. The inlet opening 98 cooperates with the end of a passage 101 formed within a tubular member 103 secured to the shaft member 40 and forming part of the stator assembly. The tubular member 102 is disposed within the shaft portion 40, which provides an annular cylindrical passage 103. As the fan rotates, air is drawn into the combustion chamber 28 via openings 104 in the flange 25. The air serves to cool and scavenge the combustion chamber, the air sweeping across the chamber, then between the pinion gear teeth 56 and member 43 to take up residual combustion products, the combustion products being discharged along the passage 101 to the fan housing then out through the exhaust port 100. The fan also draws air through inlet ports 105 formed in the shaft 40, the air passing along the passage 103 and providing a thermal barrier between the tube 102 and the stationary shaft 40.

The fan impeller 95 is driven from the engine in the following manner. Secured to the rotary shaft portion 26 is a V-pulley 106 which drives a belt 107 passing around a V-pulley 108 of a countershaft (see FIG. 3). The countershaft in turn drives a belt 109, which passes around a V-pulley 110 forming part of the fan rotor.

As in the case of other types of internal combustion engine there will be a certain degree of blowby, that is to say, gas escaping between the piston and cylinderlike elements of the compression mechanism. The present engine is designed so that there will be no loss of fuel from this cause. Referring to FIG. 8, fuel mixture escaping from pocket i to pocket h between the contoured surfaces of the gear teeth will pass into the next charge. Fuel mixture similarly escaping from pocket i to pocket j will be consumed by the burning charge in the combustion space of pocket j. However, any fuel mixture escaping between the ends of the pinion gear teeth 56 and the end walls of the combustion chamber will pass into the hollow space 111 and from there will pass via ports 112, 113 into a cavity 114 within the shaft 42. The cavity 114 communicates by way of a passage 115 with the input side-of the precompression chamber 27. In this way any fuel mixture escaping into the space 111 over the ends of the pinion gear teeth will be returned to the precompressor and recirculated.

FIG. 9 shows an alternative construction of resilient hollow pinion gear tooth. In this construction the tooth includes a rigid core 116 to which an appropriately profiled resilient band 117, acting as a spring and providing the tooth profile, is anchored by lugs 118 and secured in a central position by an integral key 119. The core 116 is formed with cavities 120 which communicate with the inner and outer surfaces of the core by ducts 121. This arrangement provides for reclamation of fuel mixture which might leak into the interspace 122 from the ends of the pinion gear tooth.

The shroud member 31 with a scrubber 123 is secured to the tubular frame members 34 by connections 124 'as shown in FIG. 4. FIG. 6 is a scrap view of the scrubber viewed on line 6- -6 in FIG. 4.

It will be appreciated that the number of pockets formed in the chambers 27 and 28 may be varied without departing from the principle of the invention. Similarly, the number of teeth of the pinion gears may be varied to suit the number of pockets. In the particular example described herein the engine gives six power impulses for each revolution of the rotor assembly, this corresponding to a twelve-cylinder four-stroke cycle engine. Such an engine of the reciprocating piston-type would have five-rotating parts and one hundred and forty four-reciprocating parts, whereas the present construction eliminates all reciprocating parts and reduces the number of rotating parts to five. A part" in this sense means a single member or an assembly-of members which are rigidly connected together to fonn a unitary structure.

In this specification the convex and concave cylindrical surfaces of the members of crescent-shaped cross section are described as being disposed in sliding contact with the teeth of the respective gears, and the ends of the pinion gear teeth are described as being disposed in sliding contact with the end walls of the cylinders. It will be appreciated that there will, in general, be a very small gap between the relatively moving surfaces; the term disposed in sliding contact is therefore intended to mean juxtaposed so as to permit relative move ment of the surfaces one across the other.

lclaim:

1. A rotary internal combustion engine comprising:

a. a stator assembly providing an axis of rotation;

b. a rotor assembly journaled to the stator assembly for rotation about said axis;

c. the rotor assembly comprising:

i. first and second coaxial, internally toothed ring gears;

ii. rigid casing means connected to the ring gears and defining therewith first and second coaxial axially spaced, cylindrical chambers,

iii. first and second pinion gears; and

iv. means supporting the pinion gears within the charm bers for rotation about axes which are parallel to said axis of rotation and radially spaced therefrom, the pinion gears meshing with the teeth of the respective ring gears and defining therewith first and second series of cyclically contracting and expanding closed pockets;

d. the stator assembly comprising a support structure and first and second members of crescent-shaped cross section rigidly connected to the support structure, said members being located within the respective chambers and each having a convex cylindrical surface positioned to make sliding contact with the teeth of a ring gear and a concave cylindrical surface positioned to make sliding contact with the teeth of a pinion gear;

e. fuel intake means including a first passageway communicating with the first chamber for supplying each of said first series of pockets in turn with fuel mixture prior to contraction of the pocket, and a second passageway communicating between the first and second chambers for supplying the precompressed fuel mixture to the second chamber; a

f. ignition means for igniting the compressed mixture in each of said second series of pockets successively; and

g. means for discharging combustion products from said second series of pockets.

2. A rotary internal combustion engine comprising:

a. a stator assembly providing an axis of rotation:

b. a rotor assembly journaled to the stator assembly for rotation about said axis;

c. the rotor assembly comprising:

i. first and second coaxial, internally toothed, involute ring gears;

ii. rigid casing means connected to the ring gears and defining therewith first and second coaxial, axially spaced, cylindrical chambers, said casing means providing four annular flanges defining end walls of the cylinders;

iii. first and second pinion gears of involute form adapted to mesh with the ring hears;

iv. means supporting the pinion gears within the chambers for rotation about axes which are parallel to said axis of rotation and radially spaced therefrom, the pinion gears meshing with the teeth of the respective ring gears and defining therewith first and second series of successively contracting and expanding closed pockets, the end walls of the cylinders sealingly engaging the ends of the ring gears and pinion gears to close the pockets;

cl. the stator assembly comprising a support structure and first and second members of crescent-shaped cross section rigidly connected to the support structure, said members being located within the respective chambers and each having a convex cylindrical surface positioned to make sliding contact with the teeth of a respective ring gear and a concave cylindrical surface positioned to make sliding contact with the teeth of apinion gear;

e. fuel intake means including a first passageway communicating with the first chamber for supplying each of said first series of pockets in turn with fuel mixture prior to contraction of the pocket, and a second passageway communicating between the first and second chambers for supplying precompressed fuel mixture to the second chamber:

f. ignition means for igniting the compressed mixture in each of said second series of pockets successively; and,

g. means for discharging combustion products from said second series of pockets.

3. A rotary internal combustion engine as claimed in claim 2, wherein the pinion gears are formed with resilient, hollow, open ended teeth, the ends of the teeth being disposed in sliding engagement with the cylinder end walls.

4. A rotary internal combustion engine as claimed in claim 2, including an induction fan arranged to be driven by the rotor assembly, the fan having a housing connected to the stator assembly, the housing having an exhaust opening, and an inlet opening, the stator assembly including a first hollow shaft communicating between said inlet opening and said combustion products discharging means, and said casing means providing air inlets to said second chamber, whereby scavenging air is drawn through the air inlets into the second chamber, sweeping combustion products therefrom, and along the first hollow shaft to the fan housing, andis discharged therefrom via the exhaust opening.

5. A rotary internal combustion chamber according to claim 4, including a second hollow shaft secured to the stator assembly and extending coaxially within the first hollow shaft to define an annular cylindrical space between the shafts, the

first hollow shaft providing radial ports for admitting external air to the annular cylindrical space to be drawn therealong by the fan so as to provide a thermal barrier.

6. A rotary internal combustion engine as claimed in claim 2, including first and second hollow shrouds connected to the support structure, the first and second chambers being provided with annular, external cooling fins integrally connected to the ring gears and casing means, and located within the shrouds.

7. A rotary internal combustion engine as claimed in claim 2, wherein the in ignition means comprises a high tension electrode, means supporting the high tension electrode on the stator assembly at a position radially offset from the axis thereof, and'a series of ignition devices mounted in an end wall of the second chamber, each ignition device including sparking means located in respective one of said second series of pockets and an external electrode, the external electrodes being positioned to cooperate with said high tension electrode in cyclic succession as the second chamber rotates.

8. In a rotary internal combustion engine:

a. a stator assembly providing an axis of rotation;

b. a rotor assembly joumaled to the stator assembly for rotation about said axis;

c. the rotor assembly comprising:

i. an internally toothed, involute ring gear;

ii. rigid casing means connected to the ring gear and defining therewith a cylindrical chamber, the casing means providing a pair of annular flanges defining end walls of the chamber;

7 iii. atleast one pinion gear of involute form adapted to mesh with the ring gear;

iv. means supporting the pinion gear within the chamber for rotation about an axis which is parallel to said axis of rotation and radially spaced therefrom, the pinion gear meshing with he the teeth of the ring gear and defining therewith and with the chamber end walls a series of contracting and expanding closed pockets;

d. the stator assembly comprising a support structure and a member of crescent-shaped cross section rigidly connected to the support structure, said member being supported within the chamber and providing a convex cylindrical surface positioned to make sliding contact with the teeth of the ring gear and a concave cylindrical surface positioned to make sliding contact with the teeth of the pinion gear;

e. said member of crescent-shaped cross section providing an internal cavity for receiving fuel mixture, and a passage communicating with the cavity, the passage terminating in a port positioned to admit fuel mixture to a pocket prior to contraction thereof;

f. fuel intake means including a passage communicating with said cavity for delivering fuel mixture thereto;

g. ignition means for igniting the compressed mixture in each of the pockets successively; and

h. means for discharging combustion products from the chamber.

9. A rotary internal combustion engine as claimed in claim 8, wherein said pinion gear is formed with resilient, hollow, open ended teeth, the ends of the teeth being disposed in sliding engagement with the cylinder end walls.

10. A rotary internal combustion engine as claimed in claim a, including a precompressor having an input and an output, the output communicating with said fuel intake means for supplying precompressed fuel mixture to said cavity, said pinion gear support means including a passageway communicating with the input of the precompressor, and said pinion gear being formed with ports communicating between the hollow pinion gear teeth and said passageway whereby to provide a recirculation path for any fuel mixture leaking into the hollow teeth.

11. A rotary internal combustion engine as claimed in claim 10, including an induction fan arranged to be driven by the rotor assembly the fan having a housin connected to the stator assembly, the housing having an ex aust opening, and an inlet opening, the stator assembly including a hollow shaft communicating between said inlet opening and said combustion products discharging means, and said casing structure providing air inlets to said second chamber, whereby scavenging air is drawn through the air inlets into the second chamber, sweeping combustion products therefrom, and along the hollow shaft to the fan housing, and is discharged therefrom via the exhaust opening. 

